All lanes of the major interstate had reopened Tuesday afternoon, but a flash-flood warning for Maricopa County - first issued early Tuesday morning - was extended to 10:45 p.m. local time, according to the National Weather Service.

Meteorologists say the heaviest of the storms have now passed.

Earlier, residents of Black Canyon City, north of Phoenix, were put on standby for evacuations from rising waters. A mandatory evacuation order was issued for the River's Edge Trailer Park by 11 a.m. and students from New River Elementary School were also evacuated late Tuesday afternoon as a precaution, in part because school officials did not want school buses to cross flooded areas.

Rock slides were also reported in the area, according to Yavapai County officials.

The rains, flooding and debris forced authorities to close or restrict traffic on nearly two dozen roadways in Maricopa County on Tuesday morning.

Tim Tait, an Arizona Department of Transportation spokesman, said there is a threat that additional rainfall could cause more problems on the roadways in the next few days.

"The best thing we can do is to monitor conditions and close roads in advance from flood waters," he said Tuesday. "Waters moved so quickly today that we had to scramble resources and personnel into place."

No vehicles were reported stuck on the highways on Tuesday, he said, and there were no reported injuries.

"Drivers did the responsible and right thing, they stopped and moved to the inside lanes to avoid the water as much as possible," he said.

The situation looked dire at 9:45 a.m. Tuesday as water started flooding down the northbound lanes of Interstate 17 north of Phoenix, reducing traffic to at least one lane. The water forced ADOT to close I-17 at Happy Valley Road at about 10:15 a.m. and though southbound lanes were reopened by 11:15 a.m., restrictions remained in place in the flooded northbound lanes.

The flooding prompted Central Arizona Project officials to alert cities to possible turbidity in the water, according to a CAP spokesman, which could require additional treatment at plants.

"There is no threat to the public from their drinking water," said Bob Barrett, a CAP spokesman. "Everybody is safe."

About 3 inches of rain fell in a watershed in the area and rushed over the banks of Skunk Creek, said Joe Munoz, a spokesman for the Maricopa County Flood Control District.

Construction crews also were working in the area and had prepared a small berm meant to divert water, Munoz said, but the berm failed.

"There's just a massive amount of water coming," he said. "Three inches of rain in the watershed is huge."

The rain from the morning forced emergency crews to respond to calls for water rescues throughout the day.

Video footage showed a minivan on one road that was submerged up to its windows. Emergency crews struggling against the current made their way to the vehicle and pulled the motorist to safety.